Colored glass which has been used as window glass of vehicles includes blue-tinted glass containing Fe.sub.2 O.sub.3 doped with CoO, green-tinted glass having a higher Fe.sub.2 O.sub.3 content than blue-tinted glass to have improved heat ray absorption, and gray-tinted or bronzed glass containing Fe.sub.2 O.sub.3, CoO, NiO, and Se as colorants.
While blue-tinted and green-tinted glass having a relatively high Fe.sub.2 O.sub.3 content has relatively high heat and ultraviolet absorbing power, there still is an eagerness to protect interior trim from deterioration due to ultraviolet light with the recent trend to luxurious trim of automobiles. To cope with this demand, glass having high ultraviolet absorbing power while satisfying the requirements for energy saving has recently been developed. Having a higher Fe.sub.2 O.sub.3 content than in conventional glass, this glass is also tinted in green.
On the other hand, gray-tinted or bronzed glass has been desired from considerations of designs of vehicles. However, having a lower Fe.sub.2 O.sub.3 content than in blue-tinted glass, conventional gray-tinted or bronzed glass has insufficient ultraviolet and heat absorption for satisfying the eagerness to protect interior trim from ultraviolet deterioration. It has therefore been demanded to develop grain-tinted or bronzed glass having high ultraviolet and heat ray absorbing power.
The present inventors previously proposed gray heat-absorbing glass containing tin oxide as a reducing agent and thereby having a high heat ray absorption, but this glass is costly because tin oxide is expensive.